This invention relates generally to mechanical locksets employed to secure doors. More particularly, the present invention relates generally to a mortise-type lockset that incorporates an internal clutch assembly.
Recent hardware trends and the Americans with Disabilities Act requirements for lever handles at both exterior and interior sides of doors have focused the market on lever operated lock mechanisms. Because both intruders and users can impose greater forces on the lock mechanism having lever operating systems, it is particularly important to provide a mechanism that is not vulnerable to being compromised intentionally or otherwise. In some cases lever operated lock mechanisms have included a mechanical clutch mounted between the operator or operating lever and the lockset. Such clutches selectively mechanically couple the operating lever to the lockset and permit rotation of the operating lever to retract the latch or bolt and allow entry through the doorway.
An example of an electromechanical type of clutch may be found in U.S. Pat. No. 5,640,863. Such separate, add on clutches work well and have the advantage of being compatible with existing locksets, allowing existing key-based security systems to be retrofitted with electronic security capabilities. Purely mechanical clutch assemblies are typically used between a lever or operator and the bolt of a lockset. Typically, if the door is locked either with a thumb turn or a key, the clutch assembly uncouples the mechanical connection between the operator and the bolt. Thus, an intruder who attempts to use brute force to turn the operating lever will realize that no amount of force will withdraw the bolt and allow entry through the doorway secured by the lockset.
In some cases known clutch mechanisms have been vulnerable, particularly after years of service, due to wearing of the individual parts thereof. This may lead to mechanisms that jam and become inoperative. In some cases, however, wear of the components may result in malfunctions such as jamming or make the assembly inoperative and prevent access to the secured side of the door or even prevent egress from the secured side to the unsecured side.
The present invention provides a lock mechanism that has a locked condition and an unlocked condition. The lock mechanism includes a housing, a latch that extends from the housing and has an extended position and a retracted position, a biasing member for biasing the latch to the extended position, and means for transferring an operator input motion to move the latch to the retracted position in the unlocked condition. The means for transferring an operator input motion includes uncoupling the operator input motion from the latch in the locked condition. The means for transferring includes a locking driver and a locker. The locking driver includes a first surface and a second surface and the locker includes a biasing member for biasing the locker toward at least one of the first and second surfaces.
More particularly, the invention may provide the locking driver with at least one of the first and second surfaces defined therein. The first and second surfaces may be arced surfaces. The first and second surfaces may be generally concentric. The locker may be a first locker and the biasing member may be a first biasing member. The lock mechanism may include a second locker that may include a second biasing member for biasing the second locker toward the other of the first and second surfaces. The first locker may be biased in a first direction and the second locker may be biased in a second direction. The first and second direction may be substantially similar. The first locker may also include a first pin and the second locker may also include a second pin. The first biasing member may be disposed in a generally coaxial relationship with the first pin and the second biasing member may be disposed in a generally coaxial relationship with the second pin.
It is another feature of the present invention to provide a lock mechanism that has a locked condition and an unlocked condition. The lock mechanism includes a housing, a latch that extends from the housing and has an extended position and a retracted position, and a displaceable locking driver that has a first position corresponding to the unlocked condition and a second position corresponding to the locked position. The locking driver is operable to transfer operator input motion to move the latch to the retracted position in the first position. The locking driver is also operable to uncouple the operator input motion from the latch in the second position. The lock mechanism also includes a locker that is interconnectable with the locking driver and includes a biasing member for biasing the locker toward the locking driver.
A further feature of the present invention is to provide a lock mechanism that has a locked condition and an unlocked condition. The lock mechanism includes a housing, a latch that extends from the housing and has an extended position and a retracted position, and an operating lever operable to provide an operator input motion to move the latch to the retracted position in the unlocked condition. The operator input motion is uncouplable from the latch in the locked condition. The lock mechanism also includes a locking driver interconnectable with the housing. The locking driver includes a first surface and a second surface. At least one of the first and second surfaces is defined within the locking driver. The lock mechanism further includes a first locker interconnectable with the locking driver. The first locker includes a first biasing member that biases the first locker toward one of the first and second surfaces. The lock mechanism further yet includes a second locker that is interconnectable with the locking driver. The second locker includes a second biasing member that biases the second locker toward the other of the first and second surfaces.